The present invention relates to an image processing apparatus and method thereof, and more particularly, to an image processing apparatus and method thereof for controlling image processing performed on inputted image data.
An image processing apparatus such as a printer or the like, which forms an image on the basis of inputted color image data, inputs R, G and B signals used as the image signals for a monitor, and processes the inputted signals to convert them into C, M, Y and K signals used as image signals for a printer. Then, the ink which corresponds to the C, M, Y and K signals obtained by the above signal conversion is subjected to subtractive mixture to reproduce the color.
FIG. 1 is an explanatory view for explaining the subtractive mixture of colors. Reference numeral 181 denotes surface of a print sheet as a recording medium; 182 to 185, black (k) ink, cyan (C) ink, magenta (M) ink, and yellow (Y) ink respectively; 186, incident light onto the print sheet surface 181; and 187, reflected light from the print sheet surface 181.
In a printer, an image is formed by superimposing the ink 182 to 185 on the print sheet surface 181. In this case, the incident light 186 transmits through the ink layers 185 to 182 until it reaches the print sheet surface 181. Then the light is reflected by the print sheet surface 181, transmits through the ink layers 182 to 185 again and reaches an observer as the reflected light 187. In this process, the ink layers 182 to 185, each of which having a different spectrum absorption characteristic, sequentially absorb energy and change the spectrum characteristics, thus reproducing colors.
FIG. 2 shows the arrangement of an ink-jet printer (hereinafter referred to as "IJP") which forms a color image. Reference numeral 151 denotes a printhead which forms an image on a print sheet 153 by discharging ink having colors of C, M, Y and K; and 152, a line-feed motor for conveying the print sheet 153 to a direction indicated by an arrow. Herein, the printhead 151 includes a plurality of nozzles as recording elements, each of which is the smallest unit of ink discharging operation, arranged such that the plurality of nozzles are arrayed to the width of the print sheet 153 with respect to each of the C, M, Y and K ink. The printhead having such arrangement is hereinafter referred to as a "wide printhead."
The IJP having the above configuration forms one line of an output image by single ink discharge from each of the C, M, Y and K printheads. The ink discharge operation is repeated in synchronization with the conveyance of the print sheet conveyed by the line feed motor 152, to form an image corresponding to one page of an image.
IJP is a printer which forms an image by discharging or not discharging ink in a unit of a pixel. In order to obtain a high quality output image, various image processing is necessary, including the process of converting inputted R, G and B image data to C, M and Y (C, M, Y and K) image data which is quantized for an IJP.
However, in the above described art, the following problem arises. While high quality output image can be obtained on account of the binary image data obtained by performing various image processing for the IJP, the print speed decreases. For instance, the various image processing are performed on original image data such as a document not including many colors. Therefore, process efficiency is poor and it is difficult to improve the print speed. In addition, in printing operation such as draft printing, where a user merely needs to confirm layout of an output image, various processing are performed, resulting in consuming more time than necessary in printing operation. The above problem arises because there has not been any means suggested to selectively utilize a print-quality-oriented image process or a print-speed-oriented image process, in accordance with the usage of an output image.